Ammonia Refrigeration and 2018 NFPA 1 (Fire Code)

The National Fire Protection Association (NFPA) recently released their publication of the 2018 NFPA 1 Fire Code and it contains two noteworthy changes from the 2015 version that will impact ammonia refrigeration systems built under the jurisdiction of this code. If your facility is already using IIAR as your primary standard for ammonia refrigeration, these changes won’t come as a shock:

1. Activation for Emergency Ventilation

Whereas 2015 NFPA 1 required machinery room ventilation systems to be activated at an ammonia concentration not exceeding 1,000 ppm, 2018 NFPA 1 §53.2.3.3.3[1] has lowered the activation concentration to 150 ppm which aligns with IIAR 2.

2. Decommissioning Systems

2018 NFPA 1 §53.3.3[2] introduced a new requirement to the Fire Code. When an ammonia refrigeration system is to be decommissioned, the decommissioning process must be conducted in accordance with ANSI/IIAR 8, Decommissioning of Closed-Circuit Ammonia Mechanical Refrigerating Systems.

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[1] 2018 NFPA 1 §53.2.3.3.3

For systems using a refrigerant other than ammonia, purge fans shall also respond automatically to the refrigerant concentration detection system set to activate the ventilation system at the threshold levels set forth in 53.2.3.1.1. For systems using ammonia, purge fans shall also respond automatically to the refrigerant concentration detection system set to activate the ventilation system at an ammonia concentration not exceeding 150 parts per million.

[2] 2018 NFPA 1 §53.3.3 Decommissioning of Ammonia Refrigeration Systems.

Decommissioning of closed-circuit ammonia refrigeration systems shall comply with ANSI/IIAR 8, Decommissioning of Closed-Circuit Ammonia Mechanical Refrigerating Systems.